Personal experiences converting from oil to propane?

Submitted by Dont_Mind_da_Lurker t3_zxau97 in massachusetts

I'm considering switching our home from oil to propane and as part of my research, I'd like to see if anyone has personal experience they'd like to share... Did you do it? If no, why not? If yes, why? What do you wish you had known at the time? Would you do it again?

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Our use would be primarily for hot water, and to provide backup heat via existing forced water floorboard radiators in case our heat pumps (our primary heat source) fail or if the weather gets too cold for them. We're also likely to put propane in anyway for an emergency standby generator, so seems like tapping into propane for hot water and backup heat wouldn't be huge.

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Most of the information I'm finding in my research is coming from companies that sell oil or sell propane, so there is a built in bias that I'm trying to sift through to find the facts... But I'm also interested in people's more subjective opinions of their own experience if you're interested in sharing them.

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Thank you!

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TLDR

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We just moved into a home built in 1997 still running the original boiler and tank (25+ years old now). The condition of the equipment itself is pretty good considering its age, but the boiler uses a tankless coil to provide hot water, and it can't keep up with our hot water demands (can't fill a bathtub before going cold, we can barely get through a quick shower before the water starts cooling). Given the older, relatively inefficient single-pass design of the boiler, and that its age is approaching end-of-life, most HVAC companies don't want to touch the boiler unless it is to remove it entirely. We're getting proposals from companies and receiving options like:

  • Replace the tankless coil with indirect hot water tank off the current boiler (which may need to be replaced in the next few/several years anyway).
  • Replace the whole boiler with a newer, more efficient design, and put in an indirect hot water tank at the same time.
  • Replace the whole boiler with a propane fired tankless water heater, and a propane fired boiler that would only need to kick-on if it gets too cold for our heat pumps or if there is a failure in our heat pumps.

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We had a natural gas fired tankless water heater at our old house and loved that we weren't keeping a tank of water hot when we weren't using hot water, and that when we did need hot water, it never ran out, so the idea of switching to a propane tankless water heater is appealing to us.

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We'd also be able to get the oil tank out of our basement so we won't run any risk of oil leaks/spills in our house going forward.

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Also, with the boiler becoming a backup heat source to our heat pumps, we're hearing oil boilers don't really like being shut off and turned back on again later, which can cause problems, leaks, etc.

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I've also seen the somewhat harder to quantify costs of more maintenance required for oil equipment vs. less maintenance required for propane equipment.

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I've researched the BTUs output and efficiency of both; i.e. I know oil is less efficient but kicks out more BTUs per gallon than Propane, which is far more efficient, but we'd still need more gallons of Propane for the same BTUs output as oil. Factoring in the price difference between the two to get price-per-BTU (as opposed to comparing price-per-gallon) using data from Mass.gov Massachusetts Home Heating Fuels Prices, historically, Propane has been on average ~38% (but as high as nearly double) more expensive per BTU than oil until the 2022 run-up in oil prices and now they're roughly on-par with each other.

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I'm also not exactly sure how to quantify the difference between the oil boiler burning oil throughout the day to keep our water tank hot vs only burning propane on-demand when we ask for hot water... but is it burning enough extra oil to erase the price-per-BTU premium we'd pay for Propane (i.e. burning more gallons of cheap oil vs. burning fewer gallons of more expensive propane)?

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Comments

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eightfingeredtypist t1_j1z9ia9 wrote

Look at air source heat pump electric hot water heaters.

Heating water to heat your water isn't as efficient as heating your water.

The boiler is expensive. Save wear and tear on it by using it less.

I used to heat the water off a gas boiler. Now the boiler sits there as a back up to to minisplits, which are a back up for the masonry heater. Solar panels mean no electric bills, no more gas bills, either.

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Dont_Mind_da_Lurker OP t1_j1ztbos wrote

I just stumbled into the idea of Heat Pump Water Heaters today too... Interesting idea... Consumer Reports show them being far more efficient and far better ROI/pay-back then either gas or electric tanks or tankless. I'll drill into that idea more as I pursue this.

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Maleficent-Guess8632 t1_j207dl9 wrote

I had heat pump water heater..personal experience tells me that there was no saving between my heat pump water heater vs regular electric water heater

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Dont_Mind_da_Lurker OP t1_j20job5 wrote

Interesting... as in, you paid just as much in electricity for both? The heat pumps are supposed to use less electricity, so would be interesting if your experience was otherwise...

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downwardspiralstairs t1_j204otb wrote

The only advice I can give is don't buy a York furnace.

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Dont_Mind_da_Lurker OP t1_j20kh76 wrote

Haha, noted... HVAC guys are all quoting out for Mitsubishis or Bosch heat pumps, so sounds like I'm in clear there :)

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March_Latter t1_j20l6hp wrote

I went with Navien. Hot water cost is negligible. My gas bill is mostly the fee's in summer. Summer actual gas cost is maybe $3 for hot water. It seems like you live somewhere other than New England so if its warm enough you can heat with mini split style heat pumps. Here you can not do so efficiently so my current gas bill is $220 for the month keeping the hundred year old 1500sf house a 69 degrees.

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Dont_Mind_da_Lurker OP t1_j20maud wrote

We're in central MA, Worcester County out in the country. Are you referring to your natural gas bill or are you on propane? We don't have natural gas out in the country, so it's either deliveries of oil or propane, or electric from the street.

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March_Latter t1_j20nd8k wrote

I am gas, but the system is the same. Just the cost of fuel is different. I understand Propane costs roughly 6 times more than Natural gas per BTU so you would need to factor that in. Mini Splits lose efficiency from 40 degrees and at 20 lose drastically. So mostly you would have to guess how many cold days you have below 20 that a system would make up for and handle hot water. I think in your odd case keeping oil might be the most cost effective idea.

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MajorProblem50 t1_j223zwi wrote

Another vote for heat pump water heater. I'll be getting it next year with the state and federal rebate.

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nattarbox t1_j1zjx78 wrote

Don't have direct experience, but a few anecdotes that might be useful:

My parents swapped from oil to propane (forced air furnace), but propane prices went up at the same time in Maine and it ended up being a wash on fuel savings. They supplement with heat pump minisplits which helps with costs a lot and makes the house cozier.

If you haven't looked into it, Mass Save is offering big rebates to convert from oil to fully electric (heat pumps). There are also heat pump options for electric water. Might be worth a pricing out to compare against propane, but with rising electric costs I'm not entirely sure what the best option is anymore.

I swapped from an electric water heater to an on-demand natural gas boiler. I like it a lot better (unlimited water, more reliable, freed up space in the basement), but the energy savings were pretty negligible. Hot water energy costs are like a rounding compared to home heating.

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Dont_Mind_da_Lurker OP t1_j1ztssr wrote

Hi, yes, we're working with HVAC companies to put in heat pumps which will become our primary heat source instead of our oil boiler... But every HVAC company has recommended we keep a backup heat source in case it gets too cold for the heat pumps, or if there is a breakdown in the heat pump equipment that can take a few or several days to repair and we wouldn't want to be without heat in the meantime... Since we have existing radiators from our boiler, they're all saying keeping a boiler as backup will be the best option... but our boiler is near end of life, and not providing enough hot water, hence this whole line of questioning and research about oil boiler vs. propane boiler.

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nattarbox t1_j205b21 wrote

Yeah not having a backup seemed like one of the sticking points for going all heat pump to get those rebates. My parents went with two condensers, so if one goes you still have the other. Something like that + cold weather heat pumps + a generator would keep you going through most any situation. Still have rising electric costs to deal with though.

If you have to keep propane in the mix, I'd go for the combo on-demand boiler, just based on my experience having a natural gas version. It cut our therms in half vs a standard older gas furnace, hopefully you'd see similar efficiency with propane. And if the minisplits are doing the heavy lifting on heat, your gas needs could be pretty minimal. There are still some valuable rebates available for a setup like that.

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Dont_Mind_da_Lurker OP t1_j20l2qo wrote

Yeah, that's pretty much the direction we're heading: Cold weather heat pumps are primary heat, need backup heat when it's too cold for heat pumps, need some source of hot water (same fuel/system as backup boiler, or something entirely different?)... Sounds like we may be on the right track...

The HVAC guys are telling us a combi unit wouldn't work well for our usage, so they're looking at tankless water heater as one unit, backup boiler as a separate unit... but we did ask about the combi units.

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individual_328 t1_j1zn961 wrote

The way things are going, fossil fuel systems are looking like poor long term investments right now. Consider going all electric with on-site generation and storage for backup (solar + batteries).

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Dont_Mind_da_Lurker OP t1_j1zucqo wrote

I agree philosophically on this... If I could get all-electric with solar we would. We did the assessment at my last house and we couldn't quite generate enough off our roof to cover our needs and pass excess to the grid. I need to have a proper assessment done on my new house here, but I don't have high hopes as we don't have any south-facing roof area... Half of our roof gets the morning sun, the other half gets the afternoon sun, and some of our roof is shielded by some trees in the wintertime when the sun is lower. Pending expert assessment, it looks like we won't get much generation off our roof. The fallback is putting panels in our yard, but we like using our yard for play area.

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individual_328 t1_j201ps3 wrote

Maybe get a small generator for emergency backup? I personally just wouldn't be comfortable putting a lot of money into any kind of new oil/gas/propane system for heat or hot water these days. It think they're all going to be obsolete in a decade and there are big credits and rebates available for switching now.

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Dont_Mind_da_Lurker OP t1_j20jin5 wrote

Yeah, small gas generator is still a possibility... but storing enough gasoline for a protracted outage is more difficult than storing propane, and propane generators can automatically kick on vs. gas I have to be home to go wheel it out and plug it in and flip circuits, etc. So there is some benefit to a propane fired generator for emergency power. Someday I'd love to be solar+battery/PowerWall... may not be in the cards for this house specifically.

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